The Mantle

The mantle is the layer located directly under the sima. It is the
largest layer of the Earth, 1800 miles thick. The mantle is composed of
very hot, dense rock. This layer of rock even flows like asphalt under a
heavy weight. This flow is due to great temperature differences from the
bottom to the top of the mantle. The movement of the mantle is the
reason that the plates of the Earth move! The temperature of the mantle
varies from 1600 degrees Fahrenheit at the top to about 4000 degrees
Fahrenheit near the bottom!